LONDON - Alex Ferguson has broken his silence on David Moyes's short, traumatic reign at Manchester United, saying the former Everton manager underestimated the size of the job while denying he retired leaving the club in decline.

In an updated version of his book, My Autobiography, Ferguson also said it was "nonsense" to suggest he hand-picked Moyes for the job alone and that no due process was involved in his appointment.

Ferguson has not previously spoken at length about Moyes's 10 months as his successor but does so in a new chapter updating the book that was published last year.

He has also denied suggestions that he left Moyes with an ageing squad and an "antiquated" club, saying that 11 of the squad that won the title in 2013 in his last season were aged 25 or under. He said Moyes just found the step up from Everton to United too big to handle.

"He hadn't realised just how big United is as a club," said Ferguson, who watched on at Old Trafford as results went against United throughout last season which ended with them finishing seventh, their lowest finish in the Premier League era.